Developing a framework to quantify the benefit cost ratio of skid resistance intervention thresholds at the network level

Research has proven that low values of pavement friction increase crash rates. For this reason, highway agencies such as the Federal Highway Administration (FHWA) and the American Association of Highway and Transportation Officials (AASHTO) have provided guidelines for the management of pavement friction, including minimum friction levels recommended for roadway networks. Following these recommendations, some state transportation agencies have established minimum friction thresholds in terms of the Skid Number (SN). Additionally, FHWA lists the Benefit-Cost Ratio (BCR) as one of the methodologies that can assist decision makers in the definition of these thresholds. However, there are limited studies conducted to quantify the BCR when determining the minimum SN threshold for a roadway network. The objective of this study is to fill this research gap by providing a methodology to quantify the BCR when establishing minimum pavement friction thresholds for roadway networks. The first step is to develop models for characterizing the deterioration of skid resistance and predict its future conditions for two scenarios: 1) base scenario where no treatments are applied, and 2) improvement scenario where treatments are applied. Benefits are estimated in terms of the monetary value of crash reductions. Costs are estimated by considering: a) the cost of applying treatments to pavement sections, b) the monetary value of travel time delays associated with work zones, and c) the monetary value of road safety risks associated with work zones. A case study was first developed to assess the accuracy of Markov Chain processes to model skid resistance deterioration. Then, the proposed methodological framework for BCR estimation was applied to a roadway network consisting of 993 highway sections in Texas as a case study to demonstrate its applicability. The case study analysis was performed for three groups of roadways: Interstate Highways, Urban Freeways, and Arterials and Collectors. The research findings indicate that the proposed methodology can provide transportation agencies with an analytical tool to effectively estimate the BCR of maintenance policies intended to establish a minimum SN for a roadway network. Moreover, an analysis was conducted to examine the impact of three alternatives that incorporate SN into the Pavement Management Plan (PMP). The results suggest that there are potential benefits of incorporating SN-related targets into the overall pavement management process.